A series of fire ant venom analogs have been synthesized for antigenic testing. Mass spectrometry has been used in the elucidation of a prostaglandin-glutathione adduct to define the composition of urushiol (poison ivy) standards for skin testing and to determine the structures of a series of new barbituric acid metabolites. Nmr has been used to identify impurities in a series of dyes used in lymphangiography.